Clamp Protection Circuit for PFC Control
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Solution Overview
Problem
Prior art voltage clamp designs in power factor correction (PFC) controllers require high voltage devices, leading to increased silicon area, cost, and limited accuracy due to high voltage stress and electrostatic discharge vulnerabilities.
Innovation Solution
A clamp protection circuit with a high voltage isolation module, a voltage clamp module, and a low voltage bias module, utilizing only one high voltage device and multiple low voltage bias modules to provide improved precision and reduced silicon area, while enhancing transient response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high voltage devices are used in the voltage clamp circuit, then the clamp protection function is achieved, but the silicon area increases and cost increases
Solution Approach 1:
The patent introduces a high voltage isolation module as an intermediary between the high voltage clamp circuit and the low voltage control circuit. This isolation module transfers the clamp function to a dedicated high voltage circuit, allowing the main control circuit to use low voltage devices, thereby reducing silicon area while maintaining clamp protection capability.
Solution Approach 2:
The patent divides the clamp protection circuit into separate functional modules: a high voltage isolation module for receiving high voltage power and a low voltage bias module for providing bias voltages. This segmentation allows each module to be optimized independently, with high voltage devices only where absolutely necessary, reducing overall silicon area.
2Reliability
If high voltage devices are used in the voltage clamp circuit, then the clamp protection function is achieved, but the cost increases
Solution Approach 1:
The high voltage isolation module acts as an intermediary that isolates the expensive high voltage devices from the main control circuit. Only the essential high voltage devices in the isolation module need to be high voltage rated, while the majority of circuit components can be low voltage devices, significantly reducing overall manufacturing cost.
Solution Approach 2:
The patent employs low voltage devices in the bias module and control circuit that are cheaper alternatives to high voltage devices. These low voltage components perform sufficient functions at lower cost, reducing the overall manufacturing expense while maintaining clamp protection capability.
3Reliability
If voltage-controlled high voltage devices are used, then the clamp protection is provided, but the clamp voltage accuracy is limited due to bias current variation, process and temperature
Solution Approach 1:
The patent implements a feedback mechanism through the bias module that dynamically adjusts bias voltages to compensate for variations in bias current, process conditions, and temperature. This feedback control stabilizes the clamp voltage at the desired level, significantly improving voltage accuracy compared to fixed bias approaches.
Solution Approach 2:
The patent dynamically changes bias voltage parameters through the low voltage bias module to compensate for environmental variations. By adjusting bias voltages in response to temperature and process changes, the system maintains accurate clamp voltage levels despite external conditions varying.
4Reliability
If device 105 forms an electrostatic discharge path, then the voltage clamp circuit works, but the device is vulnerable to ESD damage
Solution Approach 1:
The high voltage isolation module serves as an intermediary that provides galvanic isolation between the ESD-prone high voltage clamp circuit and the sensitive low voltage control circuit. This isolation barrier prevents ESD damage from propagating to vulnerable devices while maintaining the necessary voltage clamp functionality.
Data Source
AI summary
The present invention relates to clamp protection circuit and a PFC control circuit employing such clamp protection circuit. Said clamp protection circuit comprises a high voltage isolation module used for receiving power from a high voltage power supply; a voltage clamp module used for receiving an output low voltage from the high voltage isolation module and realizing a clamp protection; and a low voltage bias module used for providing bias voltage to the high voltage isolation module and the voltage clamp module. By employing the clamp protection circuit, the precision of the clamp voltage is improved, the design is simplified and the silicon area is reduced. Meanwhile, the transient response is enhanced. Moreover, when the clamp protection circuit is applied in a PFC control circuit, the design of the whole PFC control circuit is simplified and the silicon area is reduced, and the precision and transient response of the clamp voltage of the clamp protection circuit inside the PFC control circuit are improved.